Nextcloud calendar is a calendar app for the Nextcloud server platform. Due to missing precondition checks the server was trying to validate strings of any length as email addresses even when megabytes of data were provided, eventually making the server busy and unresponsive. It is recommended that the Nextcloud Calendar app is upgraded to 4.4.4. The only workaround for users unable to upgrade is to disable the calendar app.

Nextcloud talk is a chat module for the Nextcloud server platform. In affected versions brute force protection of public talk conversation passwords can be bypassed, as there was an endpoint validating the conversation password without registering bruteforce attempts. It is recommended that the Nextcloud Talk app is upgraded to 15.0.8, 16.0.6 or 17.1.1. There are no known workarounds for this vulnerability.

Nextcloud mail is an email app for the Nextcloud home server platform. In affected versions a missing check of origin, target and cookies allows for an attacker to abuse the proxy endpoint to denial of service a third server. It is recommended that the Nextcloud Mail is upgraded to 2.2.8 or 3.3.0. There are no known workarounds for this vulnerability.

Nextcloud server is an open source home cloud platform. Affected versions of Nextcloud stored OAuth2 tokens in plaintext which allows an attacker who has gained access to the server to potentially elevate their privilege. This issue has been addressed and users are recommended to upgrade their Nextcloud Server to version 25.0.8, 26.0.3 or 27.0.1. There are no known workarounds for this vulnerability.

Nextcloud is an open source home cloud server. When Memcached is used as `memcache.distributed` the rate limiting in Nextcloud Server could be reset unexpectedly resetting the rate count earlier than intended. Users are advised to upgrade to versions 25.0.11, 26.0.6 or 27.1.0. Users unable to upgrade should change their config setting `memcache.distributed` to `\OC\Memcache\Redis` and install Redis instead of Memcached.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. In Nextcloud Server starting with 25.0.0 and prior to 25.09 and 26.04; as well as Nextcloud Enterprise Server starting with 22.0.0 and prior to 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, and 26.0.4; missing protection allows an attacker to brute force passwords on the WebDAV API. Nextcloud Server 25.0.9 and 26.0.4 and Nextcloud Enterprise Server 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, and 26.0.4 contain patches for this issue. No known workarounds are available.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 20.0.0 and prior to versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a missing password confirmation allowed an attacker, after successfully stealing a session from a logged in user, to create app passwords for the victim. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 19.0.0 and prior to versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a malicious user could delete any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. As a workaround, disable app files_external. This also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 24.0.4 and prior to versions 25.0.9, 26.0.4, and 27.0.1, when a folder with images or an image was shared without download permissions, the user could add the image inline into a text file and download it. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.